First, realize that public speaking anxiety is normal and common. In fact, there are more people who fear public speaking than death. So that terrible feeling in the PIT of your stomach is happening to all the other presenters in the room. To squash those butterflies, remember PITS.
1) Practice: this is first because it is the absolute fundamental of speech delivery. Knowing your speech cold and practicing it at least 5 times is the best confidence booster.
2) Inhale: breathing relaxes the body and mind. Breathe a 7 x 7 x 7. Inhale for a count of 7, hold the breath for a count of 7 and breathe out for a count of seven.
3) Talk yourself up: give yourself a pep talk before going on stage. Tell yourself you are awesome, your talk is awesome and that you are going to deliver the speech of the year. Use your name in the pep talk: “Dave, you got this. You are the King of Public Speaking.”
4) See yourself succeeding: close your eyes and visualize yourself delivering the speech of your life, the audience hanging on your every word, laughing, nodding and thunderous applause when you finish. When you “see” success you "become" success.